A series of murders is committed in Nice on the French riviera. The commissaire Carella is in charge and tries to find a missing link between all these murders.
An aimless young man is committed to a psychiatric hospital by his father in an attempt to cure him of his delinquent tendencies.
Matou is an innocuous, gentle-looking man. He is married to a formidable, even a frightening woman, who is as dissatisfied with him as he is with her. He knows everything there is to know about restoring and authenticating manuscripts, particularly ancient ones, through his job at the museum. One day, it occurs to him that his skills could be put to use in a more personal way, and he embarks on a private career of re-arranging the documents of people who have had the misfortune to be married to the wrong people.
